Belt grinder and polisher



Dec. 5, 1950 L. D. JENSEN BELT GRINDER AND POLISHER Filed Jan. 26, 1948 H INVENTOR. .ZEJ Z7. z/Z'NSEN BY 9 6 Hr 0U V1; E l & 2 5 3 J Patented Dec. 5, 1950 BELT GRINDER AND POLISHER Leo D. Jensen, Chicago, Ill., assignor to Dover Industries, Inc., Chicago, 111., a corporation of Illinois Application January 26, 1948, Serial No. 4,430

1 Claim.

This invention relates to improvements in belt grinding and polishing machines and is more particularly concerned with a machine of this character having novel means to insure tracking of the endless grinding or polishing belt.

Machines of the character embodying the features of the present invention usually consist of a frame or housin having a plurality of related pulleys or rollers mounted therein, one of which is driven so as to drive an endless grinding or polishing belt trained thereover. A portion at least of the belt is exposed for work contact and this exposed portion is backed by a contact Wheel which may have a fiat or a contoured circumferential face depending upon the shape of the work piece. In either event, considerable difficulty and inconvenience with its consequent costly operation has resulted from the impossibility of securing proper tracking of the belt over the contact wheel. Improper tracking or weaving of the belt causes undue friction with resultant overheating and permanent damage to the belt and contact wheel. It is, therefore, an object of the present invention to provide novel structural means whereby accurate and continuous belt tracking is assured.

Another object is to provide a machine of the character described with a contact wheel fabricated from material which readily adapts the wheel for efiicient machine operation.

Known types of belt grinding and polishing machines are costly to maintain at peak efficiency because of failure to provide means whereby loose particles are discharged from the belt during op-.

eration. An accumulation of loose particles reduces the cutting efficiency of the abrasive on the belt with resultant uneven grinding or impairment in the otherwise useful life of the belt. It is, therefore, another object of the present invention to provide a machine of the kind disclosed with novel means to effect the discharge of loosened grains and waste during machine operation. 7

Other and further objects of the present invention will be apparent from the following description and claims, and are illustrated in the accompanying drawing which, by way of illus tration, shows an exemplary embodiment and the principles thereof. Other embodiments of the invention embodying the same principle may be used, and structural changes may be made as desired by those skilled in the art, without departing from the present invention and the purview of the appended claims.

In the drawing:

Fig. 1 is a side elevational view, partly broken 2 away, of a belt grinding and polishing machine embodying the features of the present invention. 7 Fig. 2 is a horizontal sectional plan view taken substantially on line 2-2 of Fig. 1.

Fig. 3 is a fragmentary front elevation View of the machine illustrating such portions thereof as are shown in Fig. 2.

Fig. 4 is a sectional detail view taken on line 44 of Fig. 3.

Referring more particularly to the accompanyin drawing, the grinding and polishing machine is contained within a frame or housing generally indicated at I I, which includes a mounting base I2 and spaced apart side walls I3. The side walls I3 are suitably cut away at I4 adjacent the front face of the machine to provide a work opening, the purpose of which will be better understood as the description proceeds. The frame or housing II is hollow and it has suitably arranged therein a plurality of rollers I5, I5 and I1. As illustrated, the roller I5 is mounted upon a spindle I 8 suitably journalled in a bearing I9 mounted on the outside surface of one of the side walls I3 adjacent the lower frame end. The roller I6 is located at the upper end of the machine frame I I closely adjacent to the front wall 20. This roller I6 likewise is suitably journalled on a spindle 21 mounted in a bearing journal 22 firmly integrally secured to one of the side walls I3. The spindle 2| is located in the frame with its axis in vertical alignment with the spindle I5. The other roller I! is arranged in substantial horizontal alignment with the roller I6 closely adjacent to the back wall 23 of the machine frame II. The roller I1 is carried firmly on a shaft '25 extending beyond one end of a motor 26 mounted, in a manner to be described hereinafter, outside the machine frame.

As best shown in Fig. 1, the motor 25 includes suitable foot portions 2? which rest upon a horizontally disposed flange or shelf 28 extending outwardly from one of the frame side walls I3. The shelf 28 is slotted as at 29 to receive anchoring bolts 3| which extend through said slots and through the foot portions 2?. This manner of mounting permits adjustment of the motor 25 forwardly and rearwardly of the housing II, although it should be evident that other means may be provided for mounting the motor for adjustment in a horizontal plane. Obviously, horizontal adjustment of the motor 26 necessitates the provision of a slotted opening 32 in the wall I3 to accommodate the roller. shaft 25 which extends therethrough.

An endless grinding or polishing belt 4| is trained over the rollers [5, I6 and IT, and over an adjustable contact wheel 32, in the manner illustrated and, depending on the position of the contact wheel 62, said belt may be tightened or loosened by horizontally adjusting the motor 26 and, consequently, the roller H, in the manner described hereinabove. It might be observed, at this time, that mounting of the roller i! on the motor shaft 25. affords a direct drive for the endless belt, which drive obviates any need for gear trains or the like for transmitting power from a remotely situated motor to the roller ii.

The endless belt 4i has one of its reaches tracked past the work opening M, thereby positioning such portion of the belt for work access. Obviously, the application of such pressure as is required to effect grinding or polishing of a work piece during operation of the belt ll would result in the belt being pushed back into the housing i I. However, backing means is provided by the novelly constructed laminated contact wheel 42, mounted in a manner to be described in detail hereinafter, so that its circumferential surface is in contact with the back face of the belt 4! as it moves. past. the work opening E4.

The contact wheel 2 is mounted for horizontal adjustment to adapt the belt grinder for grinding various types of work. For example, when fiat surface grinding is to be performed, the contact w--eel is moved forwardly substantially into the position illustrated in Fig. 1. When contour grinding is to be effected, as when a contact wheel having a contoured circumferential surface is used, the contact wheel is moved rearwardly into the machine to enable the belt to extend substantially vertically between the rollers i5 and I6 whereby it may substantially conform to the contour of the contact wheel as it passes thereover and thereby grind such contour surfaces as might be held thereagainst.

The use of a laminated contact wheel 42, as illustrated the present disclosure, is preferable, although it should be understood that the instant machine will function satisfactorily even though a soft or hard faced contact wheel fabricated of rubber, canvas, fiber wool or cotton be used. The

laminated contact wheel illustrated is fabricated from tightly held felt discs made of varying degrees of hardness so as to permit varied contact pressure between the work and the abrasive belt. The laminated felt contact wheel, which can be formed readily for contour grinding, has close with the back surface of the belt and, when pressure is applied to the belt during a grinding or polishing operation, the tendency of the belt to weave laterally is reduced to a minimum. assures continuous and uniform contact between the belt and contact wheel even in instances when the load pressure of grinding is unevenly applied. If desired, the laminated felt contact wheel may be treated to resist burning.

The contact wheel mounting also is such as will permit adjustment of the longitudinal axis thereof relative to the plane of the belt ii to further insure proper tracking of the belt over the contact wheel rollers. Such adjustment is essential in a machine of this character, irrespective of the type of contact wheel employed, because machines lacking means to control weaving and insure proper belt tracking are highly inefficient. It has been established that such weaving can be prevented upon properly adjusting the contact wheel so as to locate its circumferential surface in such planular relationship to the belt 4 as to counteract any tendency of the belt to weave laterally under the load pressure of actual grinding or polishing.

The adjustable contact wheel mounting illustrated includes a bearing bracket .3 having a spindle 46 journalled therein and extending through a slotted recess 45 in the front end of the housing wall I3. The spindle carries the contact wheel 42 on its extended end. The laminated wheel d2 may be secured to the spindle by means of a collar 46 suitably pinned thereto, as by in 4?, and a nut 48 tightened upon the threaded spindle end. This mounting of the contact Wheel affords means whereby said wheel and its spindle will rotate as a unit freely during belt operation. The bearing bracket d3 merges into a downwardly rearwardly extending body 5i having a circular base 52 which is seated upon a bearing plate 53 suitably dovetailed on its bottom face to coact with a complemental bed plate 56 firmly secured, as by bolts 55, to a shelf 5t extending outwardly laterally horizontally from the side wall I3. Structural strength is afforded the side wall I3 by connecting the shelf 53 with the shelf 28 by means of a web 5'! of substantially the same width as said shelves.

Means is provided to adjust the bearing plate along, the bed plate 5d and to this end a screw 58 having a hand wheel 59 is associated therewith whereby, upon manipulation of said hand wheel 59, the plate 53 is moved forwardly or rearwardly along the bed plate 55. Means may be provided in the form of a latch iii to. coact with the knurled edge 62 of the hand wheel 59 to resist unintended rotation of said hand wheel.

Angular adjustment of the axis of the contact wheel #12 is effected through rotatable movement of the bearing bracket 23 on the bearing plate 53. To this end, the base 52 of the bearing bracket 23 is secured to the plate 53 by a, pair of machine screws 5-3 which extend through arcuate slots 5 in the base 52 and are threadingly engaged in the plate 5-3. It should be apparent that when the screws 53 are loosened, the bearing bracket d3 may be rotatably adjusted on its mounting so as to change the angular relationship of the contact wheel with the plane of the belt. Mechanical means preferably is provided to effect such rotation of the bearing bracket 43. As shown, an arm 65 is firmly secured, as by screws 65, to one face of the bearing bracket 43 and extends outwardly and downwardly therefrom. Its lowermost extremity is provided with a suitable opening 6? to receive one end of an adjusting screw %8. The other end of said screw extends freely through a block 69 firmly mounted upon the front end of shelf 55 and has a hand wheel I! threaded upon its free end. Manipulation of the hand wheel II functions to move the arm 65 forwardly or rearwarclly, thereby rotatin the bearing bracket 4; on it mounting. After adjustment, said bearing bracket may be secured upon tightening the machine screws 63.

Means is provided in the present machine to effect automatic discharge of loose particles from the grinding and polishing belt 4i. Such removal and discharge of the loose particles is essential to avoid glazing during belt operation which frequently results in improper grinding and many rejections. To this end, a suitable vibrator may be provided to intermittently strike one reach of the belt 4! as it passes between companion rollers. In the present disclosure such means is generally illustrated at 12 and it includes a pivotally mounted lever I3 having a roller 14 on its free end adapted normally to bear against the back side of the belt, preferably that portion extending between the rollers I and IT. A solenoid 75 has its armature I6 connected to the lever 13. Current from a convenient source of electricity may be supplied to the solenoid through lead lines 11, one of which includes a make-and-break contact 18 effective to intermittently close the circuit to energize the solenoid 75 for carryin the lever 13 away from the belt 4|. When the solenoid is deenergized, upon opening of the make-and-break contact 18, a spring 79 returns the lever 13 to its initial position so as to cause the roller 14 to strike the belt with considerable force and thereby jar any loose particles therefrom. Obviously, mechanical means could be substituted for the electrically actuated belt vibrator illustrated for the purposes of disclosure.

Although an exemplary embodiment of the present invention has been illustrated in the accompanying drawing and described in detail in the foregoing specification, it should be understood that the invention is capable of embodying a wide variety of modifications in detail structure without departing from the spirit of the invention or the scope of the appended claims.

Iclaim:

In a machine of the character described the combination of a housing, an endless belt and a plurality of rollers over which said belt is trained, drive means for one of said rollers, adjustable mounting means for said drive means and said one roller a mounting integral with said housing, a bearing plate adjustably slidably mounted on said mounting, a bearing bracket adjustably rotatably mounted on the bearing the belt surface plane, and mechanical means for slidably adjusting said bearing plate toward or away from said belt.

' LEO D. JENSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 724,441 Cowgill Apr. 7, 1903 1,167,244 Zoerner Jan. 4, 1916 1,504,865 Butts Aug. 12, 1924 1,744,807 Schulte Jan. 28, 1930 1,791,917 Winsor Feb. 10, 1931 2,334,960 Roth et al. Nov. 23, 1943 2,363,728 Greenwald Nov. 28, 1944 2,367,107 Emmons Jan. 9, 1945 2,378,643 Losey June 19, 1945 2,407,499 Klossner Sept. 10, 1946 2,423,737 Tavano July 8, 1947 FOREIGN PATENTS Number Country Date 289,367 Great Britain Apr. 26, 1928 709,173 France Aug. 4, 1931- 805,369 France Aug. 22, 1936 

